Stripper drums

ABSTRACT

A crop stripper has at least one drum (6a, 6b) with several axially extending series of stripping teeth (8). The drum is rotatably in end supports. The tooth roots (26) at the ends of the drum have an edge profile inclined radially away from the adjacent supports to deflect plant stems which contact these profiles during the operation of the stripper away from the supports, so reducing the tendency for the stems to become trapped between rotor and support. A capping (32) on the support overlaps the adjacent tooth roots to assist this effect. A pair of drums can be arranged end to end with an intermediate support (14) between them and be similarly arranged to deflect plant stems away from the intermediate support. This allows increase of the operating width of the crop stripper while minimizing the risk of blockage from stems trapped between the intermediate support and the drums.

This invention relates to crop strippers for detaching and harvestingstanding crops, such grain or flowers or herbage.

Typically such strippers comprise a rotary carrier in the form of a drumwhich carries axially extending series of teeth which, as the stripperis advanced through the crop, strip desired parts such as grain, leavesor blossom from stems of the crop.

Crop strippers are made in a range of sizes and in one of its aspectsthe present invention is concerned particularly with multiple drumstrippers in which a rotor is divided into at least two carriers ordrums arranged coaxially side by side, e.g. in order to increase theoverall width of the rotor, and a bearing support separates the adjacentends of the drums.

When such multiple drum rotors are operated there is a tendency for theplant stems to be caught between two adjacent drums. The bearing supporttakes the form of a plate fixed to a casing of the stripper, so it isnot possible to avoid gaps or clearances in this region and plant stemscan become wedged between the drums and the sides of the support,leading to a blockage and even seizure of the rotor. The presentinvention is concerned with measures which can at least alleviate thisproblem.

According to one aspect of the present invention, there is provided acrop stripper comprising a rotary carrier having an axially extendingseries of stripping teeth, supports for the carrier at the ends of thecarrier, said support at least at One end of the carrier being flankedby root portions of the stripping teeth most adjacent the supportand,comprising a radially outer element which projects radiallyoutwardly of the nearest ends of said flanking tooth root portions, inthe region nearer said support the edge profile of said root portionsbeing inclined radially inwardly away from the support whereby cropstems contacting said root portion profiles are deflected away from thesupport.

More particularly the crop stripper has a rotor, whether with one ormore carriers, mounted in side supports at its opposite ends, each saidsupport being flanked by root portions of the stripping teeth mostadjacent said support and comprising a radially outer element whichprojects radially outwardly of the nearest ends of said flanking toothroot portions, in the region nearer said support the edge profile ofsaid root portions being inclined radially inwardly away from thesupport whereby crop stems contacting said root portion profiles aredeflected away from the support.

According to another aspect of the invention, in a crop strippercomprising a rotor having at least two rotary carriers arrangedcoaxially side by side, said carriers having axially extending series ofstripping teeth projecting from them, a support for the rotor extendsbetween said two carriers and is flanked by root portions of thestripping teeth most adjacent each side of the support, said supportcomprising an element projecting radially outwardly of the nearest endsof said flanking tooth root portions, in the region nearer said supportthe edge profile of said root portions being inclined radially inwardlyaway from the support whereby crop stems contacting said root portionprofiles are deflected away from the support.

In such a multiple-carrier arrangement said formation of the end rootportion profiles can be practised at the ends of each carrier, whetheradjacent an intermediate or an end support.

Preferably, said radially outer element of the or each support comprisesan outer portion extending axially towards the or each carrier tooverlap said adjoining ends of the tooth root portions.

The axial overlap of such a radially outer element can prevent thedirect entry of plant stems to the clearances between the support andthe carriers. The axial overlap of an element and the inclination of theadjoining tooth root edge profiles can therefore act in a complementaryway against the tendency of plant stems to become trapped between theplate and the carriers.

Preferably said support outer element has a radially outer surface whichis inclined radially inwardly towards the root portions of the adjacentteeth. Thus, if the support is disposed between two carriers, the outersurface may be given a substantially V-form radial cross-section toincline towards the root portions on both sides. In this way it ispossible to minimise any risk that plant stems will become lodged uponthat radial outer surface, which in extreme circumstances could lead toa build-up that could affect the operation of the stripper adversely.

For efficient stripping it is known to give the root portions of theteeth of a crop stripper re-entrant edges to form bulbous gaps betweenthe roots of adjacent teeth. In a crop stripper according to the presentinvention it is preferred to arrange that said support outer elementlies within the radial extent of such bulbous profiles at the roots ofthe associated end teeth.

A further measure which can be adopted to assist keeping the spaces atthe end teeth free from blockage is to arrange that the end teeth areoffset towards the support with the tip of each said end tooth at apitch from the neighbouring tooth of the associated row of teeth that isincreased relative to the pitch of intermediate teeth of said row. Thislimits the amount of crop that is received between the or each set ofend teeth and their adjacent support so making it easier to discard anyplant stems that have been caught up in this region.

In the foregoing references to the teeth adjacent the support orsupports, it will be understood that each end tooth can be made as asingle member or can be composed of two or more members which jointlyhave the features described, as in 8 stripper drum such as is describedin WO92/08339.

The invention will now be described by way of example with reference tothe accompanying drawings, in which:

FIG. 1 is a schematic side view of a known form of crop stripper.

FIG. 2 is a fragmentary and diagrammatic plan view of a portion of acrop stripper according to the invention showing the forward portion ofa twin-drum rotor in the region of the adjacent ends of the two drums,and

FIG. 3 is a similar fragmentary view showing another embodiment of theinvention.

FIG. 1 illustrates main components of a known form of crop stripper forattachment to a combine (not shown) or other crop collecting vehicle.The stripper comprises an outer casing 2, open to the ground, with anadjustable top cover 4. Within the casing is a stripping rotor 6comprising axial rows of stripping teeth 8 journalled at its ends in thecasing. Crop stripped by the rotor is delivered to an auger 10 by way ofa transfer conveyor 12, and from the auger the crop goes to a collectionspace (not shown) in the collecting vehicle.

Because in this example the stripping rotor has a relatively large axiallength, it is necessary to provide it with intermediate support from thecasing, typically in the form of a plate 14 which lies intermediate therotor axial length as a static bearing support. The rotor is thereforedivided into two coaxial drums of chosen lengths, e.g. each being some 3meters long. FIG. 2 illustrates a detail of the support plate 14 and thedrums 6a, 6b on each side of it.

Over the main extent of each drum 6a there are uniform axial rows of theteeth 8. The tooth pitch is generally constant but adjacent the supportplate 14 each row of teeth has a modified end tooth 20. In the exampleillustrated each end tooth occupies a width equal to the pitch p of themain series of teeth. The teeth 8 have reentrant side edges 22 in theirroot portions to form bulbous gaps 24 between them. The mutuallyadjacent end teeth 20 of the two drums are canted towards each other sothat at their closest approach their similarly re-entrant side edges 26form an entry opening to their combined root gap with an opening widthsubstantially the same as or even less than the minimum opening width tothe root gaps in the main series of teeth. The outer tips 28 of the endteeth are also offset towards each other to lie at an axial spacing nogreater, and preferably smaller, than the axial spacing between each ofthem and its adjacent tooth of the main series of teeth 8.

The support plate 14 itself has a capping 30 over its edge radiallyoutwardly of the drum. The capping has a V-section outer surface 32, thesides of that section sloping radially inwardly towards the adjacentteeth 8. The width of the capping is greater than the minimum openingwidth between the two end teeth. The form of the combined bulbous rootgap immediately adjacent the plate 14 and capping 30 is also modifiedfrom the form of the root gaps 24 of the main teeth. Radially innermostzone 34 of the tooth root gap on each side of the support plate 14 isoffset some distance from the plate. From the zone 34 towards the platethe profile of the gap is formed by a portion 36 which slopes radiallyinwards away from the plate 14 between which plate and the end face ofthe drum 6a or 6b there is a free running clearance.

The canting of the tips of the end teeth towards each other limits theswath of crop taken into the space gap between the end teeth, soreducing the load on this critical region. Moreover, by setting theminimum opening width between the teeth to less than the width of thecapping it is generally ensured that the crop stems coming between theteeth will first strike the sloping side of the capping end be deflectedby it laterally away from the support plate opening and the ends of thedrums. Most importantly, the inwards inclination of the edges of theroot gaps from their ends adjoining the support plate reduces anytendency of stems held in the root gaps to work into the clearancesbetween the ends of the drums and the plate. All these featurestherefore combine to reduce any risk of crop becoming trapped betweenthe plate and the drums and causing blockages there.

The end teeth can be formed as separate elements, as indicated in FIG.2, or can be end portions of longer comb plates formed with some or allof the main series of teeth. They can have the same radial extent as themain series of teeth, although this is not shown in FIG. 2.

Each end tooth can be formed as a unitary member, as shown in FIG. 2, orit can be compounded from a plurality of elements lying over each other,as in the case of the two-element construction of the main series ofteeth 8 in FIG. 2 with their full radial height guide tooth elements 8afronted by shorter stripping projections 8b. Further description of sucha compounded double-element arrangement of teeth is given in ourapplication WO92/08339. The tip spacing of the guide elements of the endteeth will then determine the swath width that is taken into the rootgap between the stripping projections on opposite sides of the supportplates.

FIG. 3 illustrates how similar measures to those described withreference to FIG. 2 can be provided at the outer side supports for theopposite ends of the rotor drums to provide similar protection thereagainst blockage. Parts already described are indicated by the samereference numbers.

The rotor drum 6b is indicated in FIG. 3, but of course the opposite endof the rotor 6a can be provided with precisely the same arrangement inmirror image. The modified end tooth 20' now forms with the facing sidewall 2a of the casing a restricted entry to the bulbous gap provided bythe re-entrant side edge 26. Protective rib 32a disposed radiallyoutwardly of the drum 6b corresponds to one half of the capping 30 andis disposed in the same spatial relationship to gap profile portion 36of the associated gap inner zone 34 as the capping 30 to its rootportion gap. The rotor is of course mounted with a free runningclearance from the side wall 2b. That side wall extends beyond the rib32a because it forms part of the casing for the entire strippermechanism.

The preferred form of tooth 20' shown in FIG. 3 differs from the teeth20 of FIG. 2 in two main respects. Its outer lateral apex is at asmaller offset than the corresponding point on a tooth 20 so as not tonarrow unduly the restricted gap between the tooth and the side wall 2b.If this gap is made too small there is a risk it will be blocked by thestems that enter between the tooth and the side wall. The size of thegap is similar to that between the teeth 20. Also, the outer apex of thetooth 20' is canted further outwards than is the apex of a tooth 20, sothat more crop is diverted away from the side wall 2b than is the casewith the support plate 14.

It will be understood that the arrangement shown in FIG. 3 can equallybe employed at one or both ends of a single drum stripper mechanism aswith the double drum mechanism of FIG. 2.

We claim:
 1. A crop stripper comprising a rotary carrier having anaxially extending series of stripping teeth, supports for the carrier atthe ends of the carrier, said support at least at one end of the carrierbeing flanked by root portions of the stripping teeth most adjacent thesupport and comprising a radially outer element which projects radiallyoutwardly of the nearest ends of said flanking tooth root portions, inthe region nearer said support the edge profile of said root portionsbeing inclined radially inwardly away from the support whereby cropstems contacting said root portion profiles are deflected away from thesupport.
 2. A crop stripper comprising a rotor having at least tworotary carriers arranged coaxially side by side, said carriers havingaxially extending series of stripping teeth projecting from them, asupport for the rotor extending between said two carriers, said supportbeing flanked by root portions of the stripping teeth most adjacent eachside of the support, said support comprising an element projectingradially outwardly of the nearest ends of said flanking tooth rootportions, in the region nearer said support the edge profile of saidroot portions being inclined radially inwardly away from the supportwhereby crop stems contacting said root portion profiles are deflectedaway from the support.
 3. A crop stripper according to claim 2 whereinsaid projecting element is provided with an outer surface having asubstantially V-form radial cross-section which is inclined towards theteeth of the respective carriers on opposite sides of the or eachelement.
 4. A crop stripper according to claim 2 wherein there arefurther supports at both ends of each carrier and said supports are bothprovided with radially outer elements which extend axially to overlaptheir respective adjoining tooth root portions at each end of thecarrier or carriers.
 5. A crop stripper comprising a rotary carrierhaving axially extending series of stripping teeth and mounted in sidesupports at its opposite ends, each said support being flanked by rootportions of the stripping teeth most adjacent said support andcomprising a radially outer element which projects radially outwardly ofthe nearest ends of said flanking tooth root portions, in the regionnearer said support the edge profile of said root portions beinginclined radially inwardly away from the support whereby crop stemscontacting said root portion profiles are deflected away from thesupport.
 6. A crop stripper according to any one of the preceding claims1, 2 or 5 wherein the or each said outer element extends axially towardssaid carrier to overlap said nearest ends of the tooth root portions. 7.A crop stripper according to any one of claims 1, 2 or 5 wherein the oreach said element has a radially outer surface which is inclinedradially inwardly towards the adjacent stripper teeth.
 8. A cropstripper according to any one of claims 1, 2 or 5 wherein the rootportions of the teeth have a re-entrant profile which forms bulbous gapsat the roots of the teeth and said support outer element lies within theradial extent of said re-entrant profile of the tooth root portions mostadjacent the support.
 9. A crop stripper according to any one of claims1, 2 or 5 wherein said stripper teeth most adjacent the or each supportare offset towards the support so that the tip of each said tooth is ata pitch from the tip of its neighboring tooth in the associated axialseries of teeth that is increased relative to the pitch of the tips ofintermediate teeth of said series.
 10. A crop stripper according toclaim 1 or claim 5 wherein said supports at the ends of the carrier areboth provided with radially outer elements which extend axially tooverlap their respective adjoining tooth root portions at each end ofthe carrier.